Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2016
Comparative StudyContinuous noninvasive cardiac output determination using the CNAP system: evaluation of a cardiac output algorithm for the analysis of volume clamp method-derived pulse contour.
The CNAP system (CNSystems Medizintechnik AG, Graz, Austria) provides noninvasive continuous arterial pressure measurements by using the volume clamp method. Recently, an algorithm for the determination of cardiac output by pulse contour analysis of the arterial waveform recorded with the CNAP system became available. We evaluated the agreement of the continuous noninvasive cardiac output (CNCO) measurements by CNAP in comparison with cardiac output measurements invasively obtained using transpulmonary thermodilution (TDCO). ⋯ This pilot analysis shows that CNCO determination is feasible in critically ill patients. A percentage error of 25 % indicates acceptable agreement between CNCO-cal and TDCO. The mean difference, the standard deviation, and the percentage error between CNCO-auto and TDCO were higher than between CNCO-cal and TDCO. A hyperdynamic cardiocirculatory state in a substantial number of patients and the hemodynamic stability making trending analysis impossible are main limitations of our study.
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J Clin Monit Comput · Aug 2016
Comparative StudyComparison of electrical velocimetry and cardiac magnetic resonance imaging for the non-invasive determination of cardiac output.
A novel algorithm of impedance cardiography referred to as electrical velocimetry (EV) has been introduced for non-invasive determination of cardiac output (CO). Previous validation studies yielded diverging results and no comparison with the non-invasive gold standard cardiac magnetic resonance imaging (CMR) has been performed. We therefore aimed to prospectively assess the accuracy and reproducibility of EV compared to CMR. 152 consecutive stable patients undergoing CMR were enrolled. ⋯ Gender, height and increasing CO and SV were associated with increased bias while not affecting reproducibility. Therefore, absolute values should not be used interchangeably in clinical routine. EV yet may find its place for clinical application with further investigation on its trending ability pending.
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J Clin Monit Comput · Aug 2016
Comparative StudyThe comparison of the technical parameters in endotracheal intubation devices: the Cmac, the Vividtrac, the McGrath Mac and the Kingvision.
Currently, there are plenty of videolaryngoscopes that appear on the market. They have different specifications. Some of these features favor the fact that they are more suited for educational purposes of future operators and others can be characterized with an excellent clinical use. ⋯ The C-MAC has a camera with the widest viewing angle (the OX axis-63.1, the axis OY-47.8), which in combination with the largest diagonal size of the display enables the operator to see the details relevant to clinical practice. It has also the strongest lamp intensity of the devices mentioned in this comparison (7800 Lx). In comparison of the clinical use in almost all compared parameters the Cmac D-blade is a winner, although for clinical education purpose we consider the Vividtrac a better device.
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J Clin Monit Comput · Aug 2016
Role of cerebral oxygenation for prediction of hypotension after spinal anesthesia for caesarean section.
To investigate the role of cerebral oxygen saturation (ScO2) for prediction of hypotension after spinal anesthesia for caesarean section. Forty-five parturients undergoing elective caesarean section under spinal anesthesia were selected. Blood pressure, heart rate and pulse oxygen saturation before and after anesthesia were recorded, and the association between changes in ScO2 before and after anesthesia with hypotension after spinal anesthesia was explored. ⋯ The area under the receiver operation characteristic curve was 0.83 for decrease in ScO2 for prediction of hypotension (P < 0.05), and the optimal threshold value was 4.5 %. The sensitivity, specificity, positive predictive value and negative predictive value of 4.5 % decrease in ScO2 for prediction of hypotension were 0.75, 0.78, 0.92 and 0.47, respectively. The decrease in ScO2 after spinal anesthesia is associated with hypotension after spinal anesthesia for cesarean section, and may be a clinically useful predictor.
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J Clin Monit Comput · Aug 2016
Frequency domain analysis of cerebral near infrared spectroscopy signals during application of an impedance threshold device in spontaneously ventilating volunteers.
Currently available near infrared spectroscopy (NIRS) devices are unable to discriminate between arterial and venous blood, a potential source of artifact. The purpose of this study was to test the hypothesis that oscillations in NIR signals at the respiratory and cardiac frequency could be attributed to venous and arterial blood, respectively, and thereby isolated. After written informed consent was obtained, a two-wavelength NIRS device was placed over the left frontal cortex in 20 volunteers. ⋯ There were no other significant differences between pulsatile and non-pulsatile algorithms in the estimation of StO2. In 64 % of cases, both the low (ventilator) and high (cardiac) frequency estimates of StO2 were either both larger or both smaller than non-pulsatile StO2, suggesting that they were interrogating the same vascular bed. Frequency domain analysis cannot reliably separate NIRS waveforms into arterial and venous components.